Cholesterol is an essential structural component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity. In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D.
Although cholesterol is important and necessary for human health, high levels of cholesterol in the blood have been linked to damage to arteries and cardiovascular disease. For high risk patients, their cholesterol level is routinely monitored. Standard cholesterol screening tests are conducted by obtaining a blood sample from a patient and measuring a total cholesterol level, a low density lipoprotein cholesterol (LDL-C or LDL cholesterol) level, and a high density lipoprotein cholesterol (HDL-C or HDL cholesterol) level. The LDL cholesterol is also known as “bad cholesterol” because it promotes plaque formation on the inner walls of arteries. Together with other substances, LDL-C cholesterol is thought to cause atherosclerosis. If a clot forms and blocks a narrowed artery, a heart attack or stroke can result.
There are two mechanisms that result in LDL-C in the body: production of cholesterol from the liver and absorption of cholesterol from the diet. Each mechanism can be controlled by a different LDL-C lowering drug. A common practice of health care providers is to prescribe a statin therapy to a patient with high LDL-C and to monitor the patient's response to statin therapy in order to guide future therapeutic decisions.